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81 lines
2.4 KiB
81 lines
2.4 KiB
/*
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* i8254.h: definitions for i8254 programmable interval timer in P5064
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*
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* Copyright (c) 1997-1999, Algorithmics Ltd. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the "Free MIPS" License Agreement, a copy of
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* which is available at:
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*
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* http://www.algor.co.uk/ftp/pub/doc/freemips-license.txt
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*
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* You may not, however, modify or remove any part of this copyright
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* message if this program is redistributed or reused in whole or in
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* part.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* "Free MIPS" License for more details.
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*/
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/* Timer 0 is clock interrupt (irq0)
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* Timer 1 is refresh clock
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* Timer 2 is speaker tone
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*/
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#define PT_CLOCK 0
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#define PT_REFRESH 1
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#define PT_SPEAKER 2
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#define PT_CONTROL 3
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#ifndef __ASSEMBLER__
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struct i8254 {
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unsigned char pt_counter0;
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unsigned char pt_counter1;
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unsigned char pt_counter2;
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unsigned char pt_control;
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};
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#define pt_clock pt_counter0
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#define pt_refresh pt_counter1
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#define pt_speaker pt_counter2
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#else
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#define PT_REG(x) (x)
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#endif
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/*
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* control word definitions
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*/
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#define PTCW_RBCMD (3<<6) /* read-back command */
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#define PTCW_RB_NCNT 0x20 /* rb: no count */
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#define PTCW_RB_NSTAT 0x10 /* rb: no status */
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#define PTCW_RB_SC(x) (0x02<<(x)) /* rb: select counter x */
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#define PTCW_SC(x) ((x)<<6) /* select counter x */
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#define PTCW_CLCMD (0<<4) /* counter latch command */
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#define PTCW_LSB (1<<4) /* r/w least signif. byte only */
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#define PTCW_MSB (2<<4) /* r/w most signif. byte only */
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#define PTCW_16B (3<<4) /* r/w 16 bits, lsb then msb */
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#define PTCW_MODE(x) ((x)<<1) /* set mode to x */
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#define PTCW_BCD 0x1 /* operate in BCD mode */
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/*
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* Status word definitions
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*/
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#define PTSW_OUTPUT 0x80 /* output pin active */
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#define PTSW_NULL 0x40 /* null count */
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/*
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* Mode definitions
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*/
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#define MODE_ITC 0 /* interrupt on terminal count */
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#define MODE_HROS 1 /* hw retriggerable one-shot */
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#define MODE_RG 2 /* rate generator */
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#define MODE_SQW 3 /* square wave generator */
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#define MODE_STS 4 /* software triggered strobe */
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#define MODE_HTS 5 /* hardware triggered strobe */
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#define PT_CRYSTAL 14318180 /* timer crystal hz (ticks/sec) */
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